1. Field of the Invention
The present invention relates to a combustor, a gas turbine combustor, and an air supply method for the combustor.
2. Description of the Related Art
With liberation of electric power, recent environments of power generation business shift toward increasing use of decentralized power supplies with medium and small capacities in addition to conventional large-scaled power stations with large capacities. Many of power plants with medium and small capacities employ liquid fuel that is relatively easy in handling for supply of the fuel. However, a combustor employed in the power plant using the liquid fuel accompanies the problem that the liquid fuel is deposited as carbon around a liquid fuel nozzle, and the carbon deposits adversely affect an atomization spray of the liquid fuel and a flow of air.
According to Patent Document 1; JP, A 2000-39148, a main unit of a liquid fuel nozzle is disposed substantially at the axis of a combustion burner, and an air supply nozzle for injecting air for combustion to an outlet of the liquid fuel nozzle is circumferentially disposed around the liquid fuel nozzle. Downstream of the air supply nozzle, a guide ring is disposed to deflect a flow of air toward the outlet of the liquid fuel nozzle. Fuel supplied to the liquid fuel nozzle is injected from the outlet of the liquid fuel nozzle and is burnt in a combustion chamber after being mixed with the combustion air introduced through a swirler in the combustion burner. In the combustion burner disclosed in Patent Document 1, the airflow injected from the air supply nozzle has an effect of preventing droplets of the fuel injected through the outlet of the liquid fuel nozzle from being deposited on a nozzle end face, and the provision of the guide ring contributes to increasing that effect.